EP0278366A1 — Apparatus for controlling steering of wheels of a…

Claim 1

Independent Claim 297 words

An apparatus for controlling steering of wheels of a vehicle, comprising: a steering sensor for detecting a steering angle of a steering wheel; a vehicle behavior sensor for detecting variables representing vehicle behaviors; control means comprising feed forward signal operating means provided with a steering angle signal circuit for transmitting, without modifications, a steering angle signal output from said steering sensor, a steering angle signal operating circuit having a first coefficient circuit for multiplying the steering angle signal with a coefficient, a steering angular velocity signal operating circuit having a differentiator for calculating a steering angular velocity signal from the steering angle signal and a second coefficient circuit for multiplying the steering angular velocity signal with a coefficient, and an adder for adding signals output from said steering angle signal circuit, said steering angle signal operating circuit, and said steering angular velocity signal operating circuit to output a sum signal, the sum signal being output as a feed forward signal, feedback signal operating means provided with a vehicle behavior state variable signal operating circuit having a third coefficient circuit for multiplying with a coefficient the signals for variables representing vehicle behaviors and output from said vehicle behavior sensor, said vehicle behavior state variable signal operating circuit outputting a signal as a feedback signal, and control signal operating means provided with an adder/subtracter for calculating a difference or a sum of signals output from said feed forward signal operating means and said feedback signal operating means and for outputting a steering control signal; driving means for amplifying a power of the steering control signal as an output from said control means; and actuator means for applying an optimal steering angle of either front or rear wheels or both on the basis of an output from said driving means.

Claim 2

Independent Claim 297 words

An apparatus for controlling steering of wheels of a vehicle, comprising: a steering sensor for detecting a steering angle of a steering wheel; a vehicle behavior sensor for detecting variables representing vehicle behaviors; control means comprising feed forward signal operating means provided with a steering angle signal circuit for transmitting, without modifications, a steering angle signal output from said steering sensor, a steering angle signal operating circuit having a first coefficient circuit for multiplying the steering angle signal with a coefficient, a steering angular velocity signal operating circuit having a differentiator for calculating a steering angular velocity signal from the steering angle signal and a second coefficient circuit for multiplying the steering angular velocity signal with a coefficient, and an adder for adding signals output from said steering angle signal circuit, said steering angle signal operating circuit, and said steering angular velocity signal operating circuit to output a sum signal, the sum signal being output as a feed forward signal, feedback signal operating means provided with a vehicle behavior state variable signal operating circuit having a third coefficient circuit for multiplying with a coefficient the signals for variables representing vehicle behaviors and output from said vehicle behavior sensor, said vehicle behavior state variable signal operating circuit outputting a signal as a feedback signal, and control signal operating means provided with an adder/subtracter for calculating a difference or a sum of signals output from said feed forward signal operating means and said feedback signal operating means and for outputting a steering control signal; driving means for amplifying a power of the steering control signal as an output from said control means; and actuator means for applying an optimal steering angle of either front or rear wheels or both on the basis of an output from said driving means.

Claim 3

Dependent Claim 74 words

An apparatus according to claim 1, further comprising a vehicle state detection sensor for detecting vehicle travel state variable with the vehicle travel, wherein said control means comprises gain changing means, connected to said vehicle state detection sensor and said first coefficient circuit, for changing the coefficient of said first coefficient circuit on the basis of the signals for vehicle travel state variable with the vehicle travel output from said vehicle state detection sensor.

Claim 4

Dependent Claim 99 words

An apparatus according to claim 2, further comprising an outside environmental situation detection sensor for detecting state variables representing outside environmental situations, wherein said control means comprises gain changing means, connected to said vehicle state detection sensor and/or said outside environmental situation detection sensor and said first coefficient circuit, for changing the coefficient of said first coefficient circuit on the basis of the signals for vehicle travel state variables with the vehicle travel and output from said vehicle state detection sensor and/or signals for state variables representing outside environmental situations and output from said outside environmental situation detection sensor.

Claim 5

Dependent Claim 77 words

An apparatus according to claim 3, wherein said gain changing means comprises gain changing means, connected to said first and second coefficient circuits, for changing the coefficients of said first and second coefficient circuits on the basis of the signals for vehicle travel state variable with the vehicle travel and output from said vehicle state detection sensor and/or the signals for state variables representing the outside environmental situations and output from said outside environmental situation detection sensor.

Claim 6

Dependent Claim 79 words

An apparatus according to claim 4, wherein said gain changing means comprises gain changing means, connected to said first, second, and third coefficient circuits, for changing the coefficients of said first, second, and third coefficient circuits on the basis of the signals for vehicle travel state variable with the vehicle travel and output from said vehicle state detection sensor and/or the signals for state variables representing the outside environmental situations and output from said outside environmental situation detection sensor.

Claim 7

Dependent Claim 119 words

An apparatus according to claim 5, wherein said gain changing means comprises gain changing means, connected to said vehicle state detection sensor and/or said outside environmental situation detection sensor and said steering sensor and/or said steering angular velocity signal operating circuit, for changing the coefficient of at least one of said coefficient circuits on the basis of signals for vehicle travel state variable with the vehicle travel and output from said vehicle state detection sensor and/or the signals for state variables representing the outside environmental situations and output from said outside environmental state detection sensor and the steering angle signal from said steering sensor and/or the steering angular velocity signal output from said steering angular velocity signal operating circuit.

Claim 8

Dependent Claim 127 words

An apparatus according to claim 5, wherein said gain changing means comprises gain changing means, connected to said vehicle state detection sensor and/or said outside environmental situation sensor, said steering sensor and/or said steering angular velocity signal operating circuit, and said vehicle behavior sensor, for changing the coefficient of at least one of said coefficient circuits on the basis of the signals for vehicle travel state variable with the vehicle travel and output from said vehicle state detection sensor and/or the signals for state variable representing outside environmental situations, the steering angle signal from said steering sensor and/or the steering angular velocity signal from said steering angular velocity signal operating circuit, and the signals for variables representing the vehicle behaviors and output from said vehicle behavior sensor.

Claim 9

Dependent Claim 168 words

An apparatus according to claim 3 or 7, wherein said gain changing means comprises: sense-of-situation determining means for determining a current level of a vehicle situation with reference to human senses on the basis of at least one of the signals for vehicle travel state variable with the vehicle travel and output from said vehicle state detection sensor, the signals for state variables representing the outside environmental situations and output from said outside environmental situation detection sensor, the steering angle signal output from said steering sensor, the steering angular velocity signal output from said steering angular velocity signal circuit, and the signals for variables representing the vehicle behaviors and output from said vehicle behavior sensor; vehicle state determining means for determining necessity of stability and controllability by using functions for replacing outputs from said sense-of-situation determining means into the necessity of stability and controllability; and gain deciding means for deciding gains from output values from said vehicle state determining means and outputting the gains to said coefficient circuits.

Claim 10

Dependent Claim 82 words

An apparatus according to claim 8, wherein said gain deciding means in said gain changing means comprises: a memory for calculating gain values for optimizing vehicle motion in a state of the necessity of stability and controllability and for storing calculated results; and a gain selector for selecting the gains by selecting the gain values calculated in the state of the necessity of stability and controllability from said memory, on the basis of the determination result from said vehicle state determining means.

Claim 11

Dependent Claim 70 words

An apparatus according to claim 8, wherein said gain deciding means in said gain changing means comprises a memory for storing a stability priority gain for increasing vehicle stability and a response priority gain for increasing the vehicle response, and a gain calculation section for weighting these two gains on the basis of the determination value from said vehicle state determining means and calculating gains suitable for the current situation.

Claim 12

Dependent Claim 165 words

An apparatus according to claim 2, wherein said gain changing means comprises: vehicle behavior state variable estimating means for estimating the variables representing vehicle behaviors on the basis of the steering angle signal output from said steering sensor and the signals for vehicle travel state variable with the vehicle travel and output from said vehicle state detection sensor; u estimating means for estimating a friction value (µ) between the vehicle wheels and the road surface on the basis of a vehicle behavior state variable estimation signal output from said vehicle behavior state variable estimating means and the signals for variables representing the vehicle behaviors and output from said vehicle behavior sensor; and coefficient circuit coefficient changing means for changing the coefficient of at least one of said first, second, and third coefficient circuits on the basis of an estimated u, signal output from said a estimating means, an optimal gain being supplied to said at least one of said first, second, and third coefficient circuits.

Claim 13

Dependent Claim 234 words

An apparatus according to claim 2, wherein said gain changing means comprises: means for estimating the variables representing the vehicle behaviors on the basis of the steering control signal output from said control signal operating means and the signals for vehicle travel state and output from said vehicle state detection sensor; u, estimating means for estimating a friction value on the basis of the signals for estimating the state variables being output from said state variable estimating means, and the signals for variables representing vehicle behaviors and output from said vehicle behavior sensor; slip ratio calculating means for calculating slip ratios of the vehicle wheels on the basis of the signals for vehicle travel state and output from said vehicle state detection sensor and vehicle wheel velocities, road surface shape estimating means for estimating road surface shapes on the basis of the signals for vehicle travel variables with the vehicle travel and output from said vehicle state detection sensor, and/or the sensor abnormality detecting means for detecting abnormalities of said steering sensor, said vehicle behavior sensor, and said vehicle state detection sensor; and coefficient circuit coefficient changing means for changing the coefficient of at least one of said first, second, and third coefficient circuits on the basis of an estimated µ signal output from said µ estimating means, and said slip ratio signals, said road surface shape signals and/or said sensor abnormality detection signals.

Apparatus for controlling steering of wheels of a vehicle

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